Transmission system



Jan. 8 1924. 1,480,216

J. MILLS TRANSMISSION SYSTEM Filed 001;. 11, 1916 T I T /m/en for.

l I Jalm Mil/s.

Affy.

Patented Jan. 8, 1924.

UNITED STATES 1,480,216 PATIENT OFFICE.

JOHN MILLS, OF WYOMING, NEW JERSEY, ASSIGNOR '10 WESTERN ELECTRIC COM-PANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF'NEW YORK.

TRANSMISSION VSYSTEM.

Application filed October 11, 1916. Serial No. 124,958.

will be understood from the hereinafter contained description of oneembodiment thereof comprising a wireless system in which each of aplurality of terminal stations comprises a wireless telephonetransmitting and receiving system and a wire telephone system associatedtherewith.

It is an object of the invention to prevent a circulation of powerbetween the local transmitting and receiving system or to insure thatthe signals received by a wireless receiving system will be transmittedalong the line wire in such manner as to not thereby effect thetransmission of the same signal from the local wireless transmittingsystem.

The invention provides for generating at a transmitting station acontrol tone ofla definite frequency outside of the usual talking range,preferably below, which shall be superimposed upon the original talkingcurrent impressed on the modulator of the wireless transmitter. Thecarrier wave transmitted is accordingly modulated by both the talkingand the control tone currents. Thetransmitted wave is received at adistant station Where it is detected. The detected signal currents aresent over the line wire and the simultaneously detected control currentsoperate a relay to render inoperative the local wireless transmittingapparatus by disconnecting the latter from the line wire. The localwireless transmitting apparatus is automaticall rendered operative bybeing connectedv to t e line wire upon the cessation of the detectedcontrol oscillations. Means are also provided to prevent thetransmission of energy from the sending conductor or antenna whileenergy is being received by the receiving antenna at the local Station.

, A local circulation of power. or singing,

is thereby prevented as the signal currents are confined to the linewire and cannot effeet a transmisson of energy from the localtransmitting apparatus.

Another object of the invention is to provide method and means forgenerating the control tone by means of talking currents.

This is done by supplying talking cur-- rents of suitable intensity to atuned circuit, the natural period of vibration of which is the controlfrequency. Along with the control currents thus generated will betransmitted some of the impressed talking currents. The latter aresuppressed by means of a filter which selectively transmits only thecontrol currents.

A further object is to provide novel means for and methods oftransmitting and utilizing control currents.

, Another object is to provide means for and methods of simultaneouslyefi'ectin a change in the condition of a distant station and translatingmessage currents at that station.

For further particulars of the invention, reference may be made to thedrawing, in

which, Fig. 1 indicates diagrammatically a are associated with a wiredtelephone s stem comprising a line wire 3. The hne,

3 represents any conductive system, either long or short, through whichsignal currents may be transmitted.

transmitted from the antenna 4 of the wireless transniitting system to adistant station, and si als from the distant station are adapte to bereceived by the antenna 5 of the wireless receiving-system, the receivedsignals being transferred to the line wire 3. Talking currentsoriginating in the line wire 3 are transferred bymeans of thetransformers 6 and 7 .to the circuit 8 which includes a double poleswitch 9, normally closed by means of the spring 46. By means of theswitch 9, the talking currents are supplied to a circuit including thecoils 10, 11 and 12. The coil 12 is inductively related with the coil13in the input circuit of the Signals orig mating in the line wire 3 areadapted to be amplifier 14, the output circuit of the latter beingadapted to supply amplified talking currents to the circuit 15. f

Inductively related with the coils 10 and 11 is the coil 16 whichsupplies telephonic currents to the input circuit of amplifier 17 Theoutput circuit of'amplifier 17 is adapted to supply amplified signalcurrents to a circuit including inductance 18 and, condenser 19 tuned toa frequency beyond the usual talking range and called the, controlfrequeicy. The oscillations of the control frequency are vibrations ofthe natural period I of the tuned circuit including elements 18,

currents as will hereinafter be more fully set forth. The amplifier 21is then adapted to supply amplified control currents to the circuit 23.I

The vamplifiers 14 and 21; are essentially unidirectionally conductingso that a local circulation of power in the circuit including amplifiers14, 17 and 21 is prevented. Each conductor in the circuits 15 and 23 isprovided with condensers 48, 49, and 51 as shown, whereby the directcurrents, in the output circuits of amplifiers 14 and 21, are

confined to their respective output circuits. The circuits 15 and 23 areconnected in parallel and are adapted to supply amplified talking andcontrol currents to the resistance 24 connected in the input circuit ofmodulator 25. The utility of and principles of operation of thethermionic amplifier as a modulator have been heretofore discovered byothers. Briefly, its operation, when 0011- nected in circuit as hereinindicated, depends I rent is one in which the amplitude,

upon the fact that when the device is adjusted to work upon a suitablecurved part ofthe grid potential-plate current characteristic and agiven high frequency and one or more low frequency waves are impressedupon the input or grid circuit thereof, a'component ofthe output orplate current is a current having the given high frequency, but varyingin "amplitude in accordance with the one or more low frequencies. Suchacurrent of variable amplitude is known as a modulated current. In abroader aspect, however, a modulated high frequency cfurroquency, waveform, or other characteristic is varied in accordance with a currentwave former 32, the secondary of whic of lower frequency. The generator26 of carrier oscillations is inductively associated with-theinputcircuit of modulator 25 by means of the transformer 27. The resist-Y ance 24 serves as a source of amplified signal and control currents,and since it is serially connected with the generator 26, the outputcircuit of modulator 25 is adapted to supply carrier oscillationsmodulated in accordance with both the signal and control currents. Themodulated oscillations supplied by modulator 25 may be amplified bymeans'of one or more amplifiers 28. Amplified modulated oscillations aresupplied to the sending antenna 4 by means of the transformer 29.

The carrier oscillations modulated in accordance with both signal andcontrol current transmitted from a distant station are adapted to bereceived by the antenna 5. This antenna is inductively-connected to asuitable detector 30 by means of the transformer 31. The outputtcircuitof detector 30 includes the primary windin of a transis adapted tosupply detected control and signal current to the circuit 33. Thecircuit 33 is connected through the filter 34 with the line wire 3, thefilter 34 being adapted to su press currents of filter 34 forms a bridgeconnection with the line wire 3, the latter including the artificialline 47. The artificial line 47 tends to prevent the transmission ofspeech frequency signaling current tothe circuit 8'. However, noartificial line is perfect unless it is an exact hence additional meansare provided to open circuit 8, and positively prevent the loss of theenergy of received signals therein, as well as reventing their actionupon the transmitting apparatus, or the circuit 18,

19. In advance of the filter 34 is connected the relay 35 which isresponsive tothe control currents. When relay 35 is energized, itattracts its normally open armature 36 to complete a circuit frombattery 37 to the relay 38 controlling switch 9. This opens the switch 9and renders the transmitting system 1 inoperative by disconnecting thelatter from the line wire3. When signals are no longer received byantenna 5 and relay 35 is deenergized, the spring 46 returns switch 9 toits normally closedposition. The relay 35 typifies any suitable meanswhich will be selectively operated by control currents from the remotestation. Selectivity of control currents may be effected by making useof difierences in frequency or other wave characteristic. In order toprevent any radiation of energy from the antenna 4, an armature 52- ofrelay 35 controls, through the connecting conductor 53, the circuit ofthe generator 1130 When relay 35 is energized the generator the controlfrequency. T e

circuit is opened. The means for opening the circuit 8 and the means forcontrolling the circuit of generator 26 may be used together orseparately and are typical of many possible-equivalent arrangements forcontrolling the transmitting apparatus.

The terminal station A in Fig. 2 is identical with. the station justdescribed, shown in Fig. 1. The terminal station B is similar to thestation A except as to the adjustments of its filters and its controlcurrent generator whereby the station B is adapted to transmit carrieroscillations modulated in accordance with control currents of afrequency different from those transmitted from station A,and-the-carrier wave enerated at one station is of a frequency di erentfrom that of the carrier wave supplied at the other station. Eachreceiving system is tuned to the carrier frequency. supplied by thedistant station. Furthermore, the modulated wave transmitted from.station B is adapted to be received by antenna 5 of station A, and themodulated wave transmitted from antenna 4 of station A is adapted tobereceived by the antenna 39 of station B. For simplicity, the'block 40in Fig. 2 has been used to designate all of the connections'betweenswitch 9 and transformer 29 in Fig. 1. The block 41 represents'thefilter 34 in Fi 1, and all of the connections between this filter andthe transformer 31 in Fig. 1 are represented by the block 42. The blocks43, 44

and 45 at terminal station E represent circuits which are similar to theblocks 40, 41 and 42. respectively, at station A except for theadjustment of the various elements whereby each station'is adapted togenerate and transmit both control and carrier currents of a frequencydifferent from those generated and transmitted by the other station asexplained above.

"Signal currents originating in line wire 3 will generate controlcurrents of a freuency beyond the usual talking range, and t ese controland signal currents will be transmitted from antenna 4 as modulations ofa carrier wave. This modulated wave will be received by antenna 39 atstation B where the detected control currents will be effective torender the local transmitting apparatus inoperative by disconnecting thesame from its associated line wire. The filter represented by block 44at station B insures that only the signal currents will be transmittedto the line wire to which it is connected. The transmitting apparatus atstation B becomes inoperative when carrier waves modulated by signal andcontrol currents are being received by the antenna 39.

The presence of the control currents effectuates this result. Duringsuch times the transmitting antenna at station B will not transmit anyenergy, and therefore does not affect the receiving antenna; 5 or 39. Ina similar manner, signals originating in the line wire at station B willgenerate control currents and effect the transmission of a carrier wavewhich is modulated in accordance with both the signal and the controlcurrents. This modulated wave will be received by antenna 5 at station Awhere the signal currents will be transmitted along line wire '3 and thelocal transmitting. apparatus at station A will be rendered inoperativeas long as the signal and control currents are received. As soon astalking ceases at either one of. the terminal stations, the relay at theother stag tion will be deenergiz'ed and the spring 46 will be effectiveto restore the connection of the transmitting apparatus to itsassociated line wire.

The .term telephonic currents as used herein is not limited tospeechcurrentsg but may include other currents which may be transmittedby telephone apparatus such as those used to reproduce music. obviousthat the invention maybe util'zed in connection with carrier current'or0%her wire or cable signaling systems by substi uting conductive linesfor the antennas. While one method only of producing controloscillations is disclosed herein, certain aspects of the inventioninvolve pr nci les of broad novelty which are not dependent on anyparticular method of or means for producing the control oscillations.One .such important feature comprises transmitting signals and controlenergy as energy variations of the same frequency. Control currents.

may be defined as currents or impulses of, such characteristic Orcharacterlst cs as Wlll cause a useful and desired effect other than themere reproduction of a message or part of a message at a' cooperatingstation. How-- ever, the use of control currents as defined herein isnot intended to cover the case where waves of a third frequency areintroduced and combined with a carrier wave modulated in accordance witha si nal for the purpose of securing greater l selectivity in receptionof the signal. However, vthe possible useful applications of controlcurrents according to the principles of the herein described inventionare very extensive. Certain other features of the invention are of verygeneral application and may be variously utilized.

What is claimed is:

1. The method of producing oscillationsof substantial amplitude of afrequency beyond the usual talking range which consists in impressingtelephonic currents on an otherwise non-oscillatory' circuit tuned to afre- (pjency beyond the usual talking range, t ereby producinoscillations of the free natural eriod 0 said circuit, separating saidosci ations from other oscillations, and

amplifying them.

2. A stem for producing oscillations without t e speech frequency range,comprising a space discharge repeater, a source of It wil be ectricaltelephone currents connected to the input" range which consists inilmpressing telephonic currents on a circuit tuned to a frequency beyondthe usual talking range, and

in suppressing oscillations of a frequency different from that of thenatural oscillations of said circuit.

4. A enerator of relatively low frequency oscillations comprising asource of telephonic curren'ts,-,a circuit tuned to a frequency beyondthe usual talking range, means connecting said circuit and said sourcewhereby said clrcuit is caused by said source to carry oscillatorycurrents of its natural frequency, and means for separating saidoscillations'from other oscillations.

5.111 a signaling system, the combination of a source of telephoniccurrents, a circuit tuned to a frequency beyond the usual talking range,meansfor supplying said currents to said circuit whereby currents ofsaid frequency beyond the usual talking range are generated, and meansassociated with said circuit for suppressing oscillations of; afrequenciy within the usual talking range.

6; n. a signaling system, the combination of a source of telephoniccurrents, a circuit tuned to a frequenc beyond the usual talking range,means or supplying said currents to said circuitwhereby currents of saidfrequency beyond the usual talking range are-generated, and afilterinductively associated with said circuit.

7. The combination of a line wire provid-- ing a source of telephoniccurrents, a circuit tuned to a frequenc beyond the usual talking range,means or. impressing said curs rents onsaid circuit whereby currents ofsaid frequency beyond the usual talking range" are generated, and atransmission circuit associated with said tuned circuit, said transmission circuit comprising means for suppressing oscillations-of afrequency within the usual talking range.

8. In a wireless system, the combination of sources of control, signal,and carrier oscillations, means for modulating said carrier oscillationsin accordance with both said control and signal oscillations, means fortransmitting said modulated oscillations, means at a distant station fordetecting said modulated oscillations, a signaling device for receivingthe detected signal oscillations, and means responsive to the detectedcontrol oscillations.

9. In a wireless system, the combination income of a line wirecomprising a source of telephonic currents, sources of controland-carrier oscillations, means for modulating said carrier oscillationsin accordance with said telephonic currents and with said controlosillations, a conductor adapted to transmit said modulatedoscillations, a conductor adapted to receive said transmitted modu latedoscillations, means for detecting said telephonic currents and saidcontrol oscillations, at line wire adapted to transmit said detectedtelephonic currents,and means responsive to said detected controloscillations. v

10. In a high frequency signaling system, the combination of a source oftelephonic currents,.a circuit tuned to a frequency beyond the usualtalking range, means for supplying said currents to said circuit, asource of carrier oscillations, means for modulating said carrieroscillations in accordance with the natural oscillations of said tunedcircuit, and a sending conductor adapted to transmit said modulatedoscillations.

11. In a high frequency signaling system, the combination of a source oftelephonic currents, a circuit tunedto a frequency beyond the usual-talking range, means for supplying said currents to said circuit, afilter adapted to suppress oscillations ofa frequency within the usualtalking range and adapted to transmit the natural oscillations of saidtuned circuit, a

- source of carrier oscillations, means for modulating said carrieroscillations in accordance with said natural oscillations, and a sendingconductor associated withsaid modulating means. I,

12,111 a telephonesystem, the combination of a source oftelephonicjcurrents, a cir' cuit tuned ton frequency beyond the usualtalking range, means for supplying said currents to said.. c'ircuitwheneby currents of said frequency beyond -the.;usual talking range aregenerated. a filterfladapted to suppress oscillations of a frequencywithin theusual talking range and adapted'to transmit the naturaloscillations of said tuned circuit, and

a circuit comprising means for combining said telephonic currents andsaid natural oscillations. v

. 13. In a telephone system, the -combina-. tion of a source oftelephonic currents, a circuit tuned to a frequency beyondthe usualtalking range, means for supplying. said currents to said circuit, afilter adaptedto supe press oscillations of a fre uency within the usualtalking range and a apted to transmit the natural oscillations of saidtuned circuit, a generator of carrier oscillations, means for modulatingsaid carrier oscillations in accordance with said telephonic currentsand natural oscillations, and means for transmitting said modulatedoscillations 14:. The combination of an asymmetrically ice conductingcircuit adapted to transmit telephonic currents, a second asymmetricallyconducting circuit comprising means for tuning the same to a controlfrequency, a source of telephonic currents for supplying said circuits,and a circuit supplied by said asymmetrically conducting circuitswhereby said telephonic currents and control currents are superimposed.

15. In a telephone system, the combination of a circuit adapted totransmit telephonic currents, said circuit comprising a thermionicamplifier, a second circuit comprising means for tuning the same tov acontrol frequency and a thermionic amplifier, a source of telephoniccurrents adapted to supply said circuits, and a sending circuitassociated with the output side of said amplifiers whereby amplifiedtelephonic and control currents are combined in said sending-circuit.

16. The combination'of an asymmetrically conducting circuitadapted totransmit telephonic currents, a second asymmetrically conducting circuitadapted to transmit control currents, said second circuit comprisingmeans for tuning the same to a control he quency and means forsuppressing telephonic currents, a source of telephonic currents forsupplylng said circuits, and a sending circuit connected tobe suppliedby said asy-mmetrically conducting circuits, said asymmetrical circuitsbeing so connected as to preof a line wire, a sen v ce vmg antennaassoclated with said line vent a local circulation of currentstherethrou h.

17. n a signaling system, a terminal station comprising a telephonetransmitting and receiving system, and means responsive to anenergization of said receiving system for rendering said transmittingsystem inoperative, but leaving said receiving-system I operative.

18. In a high frequency signaling system, a terminal station comprisinga radio telephone transmitting and receiving system, a Wire telephonesystem associated with said radio telephone system, and meansautomatically operating by virtue of energy received by said. receiving3 stem for control ling the transmission 0 signaling waves from saidwire' telephone system to said transmitting system. i g

19. In a telephone system, the combination of a line wire, a receivingconductor adapted to receive modulated carrier waves and to transmitsignals to said line wire and a sending conductor adapted to transmitsignals from said line wire as modulated'carrier waves, and meansautomatically operating when signals are received by said receivingconductor for controlling the operative connection of said sendingconductor to said line wire.'

- 20. In a telephone system, the combination ing antenna and a rewire,and means comprising a relay for automatlcally preventmg thetransmlsslon of energy from. said sending antenna-while enu energy wiretelephone system associate with said radio system, said transmittingsystem comprising a modulator and an'antenna and said receiving systemcomprising an antenna anda detector, and meansv responsive anenergization of said receiving system to pre vent the transmission ofenergy from said I sendin system;

23. n a high frequency signaling system, I

the combination of. a line wire, a sendin conductor and a receivingconductor associated with said line wire, a distant source of controloscillations and of signal oscillations, and means responsve to thereception of control oscillations from said source by said receivingconductor for preventing the transmission of en conductor.

24.- In a high frequency signaling system, the combination of a linewire, a sending conductor and a receiving conductor associated with saidline wire, a distant source of control oscillations and of signaloscillations, and a movable member r onsive to, the reception of controloscillatlons from said source by said receiving conductor for preventingthe transmission of energy from said sending conductor.

25. In a high frequency signalin a terminal station comprising a inewire rgy from said sending system,

adapted to transmit signal oscillations and y a te ephone transmittingand receiving system; said transmitting system compris ng a generator ofcontrol osc1llations,'a generator of carrier oscillations, means formodulatmg said carrier oscillations in accordance withfsaid signal andcontrol oscillations and a conductor adapted to transmit said modulatedoscillations; said receiving system comprising a conductor adapted toreceive modulated signal and control oscillations, the frequency ofthe'latter being different from that of aid generated controloscillations; and means responsive to said received control oscillationsfor preventing the transmission of oscillations from said sendingconductor. a

26. In a highfrequency signaling system, a terminal station comprising ame wire adapted to transmit signal oscillations and s nesoa'ieoscillations; means for preventing the transmission of the receivedcontrol oscillations to 7 said line wire; and means responsive to saidreceived control oscillations for preventing the transmission ofoscillations from said sendin conductor.

27. n a high frequency signaling system, a terminal station comprising aline wire adapted to transmit signal oscillations and a telephonetransmitting and receiving system; said transmitting system comprising agenerator of control oscillations, a gen= erator of carrieroscillations, means for modulating said carrier oscillations I inaccordance with said signal and control oscillations and a conductoradapted to transmit said modulated. oscillations; said receiving systemcomprising a conductor adapted to receive modulated signal andcontrol-oscillations, the frequency of the latter being different fromthat of said generated control oscillations; and a movable memberresponsive to said received control oscillations to render saidtransmitting system inoperative.

28. In a wireless signaling system, the combination of a line wire, atelephone transmitting and receiving system, a receivcombinationof' aline wire, a telephone I ing: conductor, anda sending conductorassoclated w th said line wire, a distant source of control and signaloscillations adapted to supply said receiving conductor, andmeansresponsive tothe reception of control OSCil. lations from saidsource by said receiving conductor for preventing the transmission ofenergy from said sending conductor.

29. In a wireless signaling system, the

transmitting and receiving system, a receivinn conductor, and a sendingconductor associated with said'lin'e wire, a distant source of controland signal oscillations adapted to simultaneously supply said receivingcon .ductor, and means rnsive to the reception of control oscillationsfrom said source by said receiving conductor for preventing thetransmission ofienergy from said sendmg conductor.

30. In a wlreless signaling. system. the combination of a line wire, atelephone transmitting and receiving system associated with said linewire, a distant source of control and signal oscillations apted tosupply said receiving conductor, and means responprising a line wire,

sive to the reception of control oscillations by said receivingconductor for preventing the transmission of energy from said sendingconductor, and means for transmission of the receive iations to saidllne wire.

( ipreventing the control oscil- 31. In a high frequency signalingsystem,

a plurality of terminal stations each comprising a wireless telephonetransmitting and receiving systemand a wire telephone system adapted totransmit telephonic currents associated with said wireless system; oneof said terminal stations comprising a source of control oscillations, agenerator of carrier oscillations, means for modulating said carrieroscillations in accordance with said telephonic currents and controloscillations, a conductor adapted to transmit said modulatedoscillations; the receiving s stem at another of saidstations being aapted to said stations responsive to oscillations'received from anotherof said stations to renand der the local transmitting systeminoperative. I i

33. In a high frequency signaling system, a pluralit of communicatingterminal stations eac comprising a radio telephone transmitting andreceiving systemv and a wire telephone s stem associated with said radiosystem, an means at each of said stations for automatically controllingthe operative connection 'of the wire system to the local transmittingsystem when energy is received from another of said'stations.

34:. In a telephone system, a plurality of communicating terminalstations each coma sending antenna and a receiving antenna associatedwith said line wire, and means comprising a movable memher at each ofsaid stations for automatically preventing the transmission of energyfrom a sending antenna while the local receiving antenna is receivingenergy from I another station.

said receiving system comprising av conductor for receiving detectingthe received oscillations, and

means responsive to the detected control oscillations for acting uponthe local transmitting system, the control currents supplied by thesource at one of said stations being of a frequency difierent from thatof the control currents supplied at the relations, means for modulatinsaid carrier oscillations in accordance with said telephonic and controlcurrents and means for transmitting said modulated oscillations; saidreceiving system comprising a con ductor for receiving the modulatedoscillations transmitted from another station,

means for detecting the received oscillations, and means responsivetot-he detected control oscillations for preventing the transmission ofoscillations from the cal transmitting system; the control currentssupplied by the source at one of said stations being of a frequencydifferent from that of the control currents supplied at the remainder ofsaid stations.

35 terminal stations each comprising a line wire adapted totransmittelephonic our- 37. In a signaling system, a plurality of rents,a telephone transmitting and receiving system associated with said lineWire; said transmitting system comprising a source of control currents,a generator of carrier oscillations, means for modulating said carrier0scillations in accordance with said'telep'honic and control currentsand means for transmitting said modulated oscillations; said receivingsystem comprising a conductor for receiving the modulated oscillationstransmitted from another station, means for detecting the receivedoscillations; means for preventing the transmission of said controloscillations to said line wire and a movable memberresponsive to thedetected control oscillations for preventing the transmission ofoscillations from the local transmitting system while modulatedoscillations are being received; the source at each of said stationssupplying control currents of a fre-' quency dlfi'erent from thatsupplied at the remaining stations.

38. In a signaling system, a plurality of terminal stations eachcomprising a line wire adapted to transmit telephonic currents,

a telephone transmitting and receiving system associated with said linewire; said transmitting system comprislng a source of modulatedoscillations" transmitted from another station, meanstor .c'ont'rolcurrents, a generator of carrier oscillations, means 'for modulatingsaid carrier oscillations in accordance with said telephonic and controlcurrents and means for transmittin said modulated oscillations; saidreceiv ng system 7 comprising a conductor for receiving the modulatedoscillae tions transmitted from another station, means for detecting thereceived oscillations, and a relay responsive to the detected controloscillations for disconnecting the local transmitting system from itsassociated line wire; the source at each of said terminal stationssupplying control currents of a frequency different from thatsupplied bythe others.

3 9. In a high frequency signaling system, a terminal station comprisinga Wireless telephone transmitting and receivingfsystem, and meansautomatically operating under the influence of energy received by saidreceiving system for controlling theoperation of said transmittingsystem.

40. The method of signaling which comprises supplying impulses, atelephone signal and carrier waves and in causing the telephone signalto produce modulation of the carrier waves by the impulses.

41. The method of signaling which comprises supplying sustalnedoscillations, a telephone signal and carrier waves and in causing thetelephone signal to produce modulation of the carrier waves both by thesignal and by the impulses during the continuanceof said si a1.

42. The method of signaling which comprises supplying sustainedoscillations, a telephone signal and carrier waves, deriving saidoscillations from said telephone signal and in modulating said waves inaccordance with said oscillations.

43. A signal transmission system comprising the combination at thetransmitting station of means for supplying a carrier wave, means formodulating said carrier Wave in accordance with both a message and withcontrol impulses, means for impressing the resulting energy upon atransmitting medium, and means at a cooperating receiv-- in stationcontrolled by the control impu se energy for-varying the receivingcondition for the energy representing the message.

44. A signaling system comprising a modulator, means for supplying highfrequency waves to said modulator, a plurality quency waves to said,modulator, and a pluparallel connected -with said of sources ofmodulating waves, a plu- 4 1' rality of paths in parallel connected tosaid modulator for leading modulating waves first named current mittingenergy each of said paths being unsymand another path for from saidthereto, metrically conducting, leading high frequency Waves means tosaid modulator.

4:6. A signaling system comprising a modulator, meansfor' supplying highfrequency wavestov said modulator, a plurality of paths connected inparallel for supplying modulating. impulses to said modulator, a vacuumtube repeater 'in each of said paths, and unlike sources of modulatingimpulses connected to each of said paths. 1

47. The method which comprises producing at a transmitting stationcurrent of a characteristic which will operate receiving apparatus at adistant station, causin said current to generate other current whic willnot operate said receiving apparatus, transfrom which similar currentscan be derived at a distant station, deriving said currents at saidstation, utilizing said to eperate-receiving apparatus, and utilizingsaid other'current to control apparatus other than said receivingapparatus at said distant station.

48. In a signaling system, a plurality oi stations, each of saidstations comprising a source of signaling current, means at each of saidstations actuated by said source for generating control oscillations,and means at each station responsive to the generation of controloscillations at another of said stationsto prevent the operation of thelocal means for generating control oscillations.

49. in a carrier current system, a pair of stations, means at one ofsaid stations-for producing carrier oscillations and controloscillations, means for modulating the carrier oscillationsin accordancewith the con" troloscillations, energy transmitting means at the otheror said stations, means for de-' riving control oscillations from saidmodulated oscillations, and means operative under the influence of saidderived oscillations for controlling the transmission of signals fromsaid other station to said one station by said energy transmittingmeans...

50. Themethod of signaling which comprises simultaneously varying theamplitude of the oscillations of a continuous alternat ing current inaccordance with both signals and control impulses and preventing theproduction of control impulses when signals are not being sent.

51. The method of signaling which com prises simultaneously andconcurrently varying the amplitude of the'oscillations of a continuousalternating current in accordance with both signal and control energyand separating and cooperatively utilizing the signal and control energyat a receiving station.

52. The method of carrier wave signal ing which comprises producingsignals and control energy and transmitting the signals inseam and thecontrol energy concurrently and not separately as variations of thecarrier Wave.

53. The method of carrier Wave signaling which comprises producing andtransmitting through a common medium sign'als and control energysimultaneously as variations of thecarrier wave, and separating andseparately but cooperatively utilizingvthe signal' tion of means forsupp ying a carrier wave,

means-for causing energy variations of said carrier Wave in accordance wth signals,

means for causingenergy variations of said carrier wave in accordancewith control oscillations of a difi'erent frequency than the signals foraffecting a cooperating receiving station, meansfor separating thecontrol oscillation energy from ener of signaling frequency at areceiving station, and causing"these energies to produce difterentresults contributing to the reception ofthe message represented by theenergy of signaling frequency. i

56 In a signaling system, the combination of means at a transmitter forsupplying a current ofa iven frequency, means at the transmitter orvarying the energy content of said current for transmitting signals, andmeans at the transmitter controlled by said second-mentioned means forcausing variations of ener y content of said current in accordance withcontrol variations.

5?. lln a transmitting system, the combi nation of means for supplying acarrier wave, means for modulating the carrier wave in accordance with awave to be transmitted,

and means for simultaneously modulating the carrier wave in accordancewith control impulses for maintaining a cooperating receiving station ina condition adapted for receiving.

58. In a signaling system, the combina tion of means for supplyingacurrent of a given frequency, means for concurrently varying the energycontent of said current for transmitting signals, and means for causingvariations of energy content of said current in accordance with controlvariations for maintaining a cooperating receiving station in a suitablecondition for re ceivin 59. tion of means for supplying a. current of agiven frequency, means for varying the energy content of said currentin'accordance li; a signaling system, the combina-' with messagecurrents, means for 'varying the energy content of said current inaccordance with control impulse energy, a cooperating, station adaptedto receive the message represented by said message currents, saidstation including means operated by the reception of said control energyfor Y waves impressed upon one of said low fre- 7 quency lines to theother thereof, and devices responsive to the transmission of signalingwaves in one direction through one of saidchannels for rendering andmaintaining the other of said channels incapable of transmission.

61. A system comprising two low frequency lines, a high frequency systemconnecting said lines normally operative for the two-way transmission ofsignals between said lines, and devices responsive to the transmissionof signaling waves in one direction through the system for rendering thehigh frequency system inoperative for transmitting in the otherdirection.

62. A telephone system comprising two speech-frequency circuits, two-waytransmission apparatus normally conditioned for reproducing in either ofsad circuits speechfrequency waves corresponding to those" in the otherthereof by transmitting between said circuits waves modulated inaccordance with speech-frequency currents existing in the circuit at thetransmitting terminal, and devices controlled by and responsive totransmission in one direction for establishing and maintaining acondition unsuitable for transmission in the opposite direction.

63. A signaling system comprising twocircuits adapted to carry currentsof comparatively low frequency, two-way transmission apparatusnormallyconditioned for reproducing ineither of said circuits signalscorresponding to those impressed upon the other thereof by transmittinghigher frequency waves varied .in accordance with the low frequencywaves impressed upon the circuit at the transmitting station, andcircuit-varying devices responsive to transmission in one direction fordisestablishing the normal condition for transmissionjin the oppositedirection.

64. A radiant energy system comprising two stations each normallyadapted to transmit radiant energy signals and to receive radiant energvsignals transmitted from the other thereof, and means at one of saidstations responsive to the reception of signals from the other of saidstations for rendering and maintaining the receiving station inoperativefor transmission.

65. A telephone iysteni .comprising "two stations each norma y adaptedto transmit modulated high frequency waves and to receive and. translateinto speech-frequency currents modulated high frequency wavestransmitted from the other of said stations, and devices at one of saidstations responsive to the reception of waves from the other thereof tochange said station from the normally operative to an inoperativecondition for transmitting.

66. A system comprising two communicating stations, means at one of saidstations for transmitting carrier frequency waves, means operable underthe influence of sound waves to vary said waves in accordance with awave having a form characteristically different from said sound waves,and means at the other of saidstations operable under the influence ofsaid varied waves to effectuate a result other than the reproduction ofsound. v

67. A system comprising two stations,

.means at one of said stationsfor producing signaling frequency wavesand carrier waves, means-operable under the influence of said signalingwaves to cause non-signaling variations'in said carrier waves, a relayat the other of said stations, and means selectively operable by thereception of said waves having non-signaling variations. to actuate saidrelay. 68. A system comprising means for .producing voice currents orwaves, means responsive to the production of voice currents for prucing, varying in accordance with said voice currents and othercurrents, and radiating high frequency waves, a circuit. at a receivingstation, means responsive to the production of voice waves at saidtransmittings'tation to reproduce said waves, and means for reproducingsaid other currents and separatelv utilizing the energy thereof to varythe condition of said circuit.

69. The method of receiving modulated high frequency waveswhich'comprises deriving speech waves and otherwaves from the modulatedwaves, utilizing the speech waves to reproduce speech, and utilizing theother waves to maintain the receiving sta- 'tion in a more effectivereceivlng condltion than during the absence of said other waves.

70. The method of signaling which comprises producing a carrier wave anda signal wave and causing the si al to produce a plurality of sets ofvariatlons in the carrier wave, one of said sets being capable ofreproducing the signal at a receiving station,

so 'I ceiving station operative by and responsive characteristics otherthan voice currents,

said source being operable under the influence of voice currents toproduce such other currents, a third source of i currents, and means forcombining the voice and other currents with currents from said' thirdsource.

74. in a telephone system, a source of voice current, transmissiondevices, and means operable under the influence of voice waves producedby said source to-cause said transmission devices to transmit a currentor wave from which a control current having characteristics other than avoice currentv may be derived at a distant intercommunh eating station.

75. in a signaling system, a source of electrical waves, a modulator, aplurality of paths between said sourceand said modulator, and meanswhereby said source causes waves of difierent characteristics to betrans mitted through said paths to said modulator. v

76. Thecombination of a source of waves, another source of waves of afrequency difierent from said first mentioned source operative under theinfluence of the production of waves by said first mentioned source anda third source of waves with a combining device and cans for impressingwaves from-said sources upon said combining device.v

77. In atransmitting system, a carrier wave source and a source of voicewaves in combination with means operative under the influence ofwavesfrom said second mentioned source to cause modulation of the carinseamrier waves in accordance with waves other than voice Waves.

means operable by and during the transmission of energy of a definitecharacteristic from another ofsaid stations for rendering thetransmitting circuit of said one station inoperative.

80'. in combination, a telephone line, a radio transmitting meansincluding a radiation system, a radio receiving means including anabsorption system separate from said radiation system, means fornormally connecting said line simultaneously to said radio transmittingand receiving means to permit radio telephony in either direction, andmeans other than a balancing circuit in said connecting means to preventsignals received by said receiving means frombeing transmitted to saidtransmitting means over said connecting means.

81. The method of signaling by electromagnetic waves which comprisesradiating signaling waves from one station and thereby renderinginoperative another transmitting station during the continuance ofsignal radiation from the first-named station.

82. The method of signaling by electromagnetic waves which comprisesradiating carrier waves from one station, intermittently modifying thecarrier waves by means of signals, and maintaining another transmittingstation inoperative during the time the transmitted waves are modifiedbut not during the time unmodified waves are transmitted.

In witness whereof, it hereunto subscribe my name this 9th day of@ctober, A. 'D., 1916; l

' JOHN Mints.

